Drayton Wiser Thermostat Kit 2 with OpenTherm

[abracadabra123]

Hi,

So I am looking to buy the Drayton Wiser Smart thermostat kit 2 for System boiler and separate hot water tank.

I have a Veissmann Vitodens 100 system boiler which looking at the wiring has the wires for Opentherm capability.

However, I've read online that the thermostat kit 2 doesn't support OpenTherm.

Does anyone know what is the actual limitation of the kit 2 to support OT?

If I was to wire OT from the boiler to the thermostat what would actually happen?

Any other alternatives to this thermostat that do support OpenTherm for system boilers and do not always require internet connection.

 

[Rodders53]

https://www.diynot.com/diy/threads/opentherm-compatibility.632660/ may help explain a little?

I found this https://charliediyte.co.uk/blog/blog/drayton-wiser-update-14-month-review quite enlightening.

My oil burner can't support OT but my Wiser 3 has the module

Open standards: the bane of manufacturer proprietary ecosystems.

 

[abracadabra123]

Thanks, very useful.

Doesn't seem to explain what would actually happen if I was to wire up like this.

 

[Rodders53]

It'll depend on if the boiler and Wiser speak the same Opentherm language (version / year / instruction set).
All the Wiser manuals suggest they should work together but other reports online say otherwise and only the Combi works? No idea why not myself.

You'd be best asking both makers and hoping that one of the pro plumber installers here have tried?

Nest 3 allegedly does work with Opentherm and Viessmann if that's worth anything.
(Even the Wiser doesn't have full feature availability if internet is lost.)

Another control I have seen mentioned for Opentherm and Viessman is https://www.wundasmart.co.uk/ You'll need to do your own research and due diligence with that device though!

 

[abracadabra123]

It'll depend on if the boiler and Wiser speak the same Opentherm language (version / year / instruction set).
All the Wiser manuals suggest they should work together but other reports online say otherwise and only the Combi works? No idea why not myself.

You'd be best asking both makers and hoping that one of the pro plumber installers here have tried?

Nest 3 allegedly does work with Opentherm and Viessmann if that's worth anything.
(Even the Wiser doesn't have full feature availability if internet is lost.)

Another control I have seen mentioned for Opentherm and Viessman is https://www.wundasmart.co.uk/ You'll need to do your own research and due diligence with that device though!

Thanks, will check with Veissmann.

Drayton's response seems to be its not currently but it may in the future.

I considered Nest 3 but read that Google was not providing updates anymore for Europe region.

 

[Mister Banks]

There are a lot of things that Drayton claim to be working on but nothing has changed since I installed Wiser 2 years ago.